Method of constructing light-measuring look-up table, light-measuring method, and light-measuring system

Abstract

The invention discloses a method of constructing light-measuring look-up table, a light-measuring method, and a light-measuring system. The method of constructing light-measuring look-up table is to construct a look-up table by according to spectrum parameters relative to a light spectrum model, three actual color-matching functions relative to the light-measuring system and three standard color-matching functions, calculating both a look-up color coordinate and a reference color coordinate corresponding to each of the spectrum parameters. The light-measuring method includes: first, measuring a to-be-measured light by the light-measuring system to obtain actual stimulus values and calculating an actual color coordinate; then, comparing the actual color coordinate with the look-up color coordinates to determine both a to-be-measured light spectrum parameter and an estimated color coordinate relative to the to-be-measured light; furthermore, according to the to-be-measured light spectrum parameter, one of the standard color-matching functions and one of the actual stimulus values, calculating an estimated luminance.

What is claimed is: 
     
       1. A light-measuring method for measuring a to-be-measured light by a light-measuring system according to a look-up table comprising a plurality of spectrum parameters and a plurality of look-up color coordinates based on a light spectrum model, each look-up color coordinate corresponding to one of the plurality of spectrum parameters, the look-up table further comprising a plurality of error corrected parameters, each error corrected parameter comprises three reference error values and corresponds to one of the plurality of spectrum parameters, the light-measuring method comprising the following steps of:
 measuring the to-be-measured light by the light-measuring system, for obtaining actual stimulus values, and then calculating an actual color coordinate; 
 determining at least one of the look-up color coordinate matched with the actual color coordinate according to the actual color coordinate and the look-up table; 
 determining a to-be-measured light spectrum parameter according to at least one of the spectrum parameters of at least one of the matched look-up color coordinates; 
 determining three error values according to at least one of the error corrected parameters of the at least one of the matched spectrum parameters; and 
 correcting the three actual stimulus values according to the three determined error values and calculating an estimated color coordinate of the to-be-measured light. 
 
     
     
       2. The light-measuring method of  claim 1 , further comprising the following steps of:
 measuring the light-measuring system to obtain three actual color-matching functions; and 
 calculating the plurality of the corresponding look-up color coordinates according to the three actual color-matching functions and the plurality of spectrum parameters. 
 
     
     
       3. The light-measuring method of  claim 2 , further comprising the following step of:
 normalizing the three actual color-matching functions by a standard light. 
 
     
     
       4. The light-measuring method of  claim 1 , wherein the light spectrum model comprises a central wavelength variable and a half-power full waviness width variable. 
     
     
       5. The light-measuring method of  claim 1 , further comprising the following steps of:
 calculating three error values according to the to-be-measured light spectrum parameter, three actual color-matching functions and three standard color-matching functions; and 
 calculating an estimated color coordinate of the to-be-measured light according to the three actual stimulus values corrected by the three error values. 
 
     
     
       6. The light-measuring method of  claim 1 , further comprising the following step of:
 calculating the plurality of corresponded error corrected parameters according to three actual color-matching functions, three standard color-matching functions and the plurality of spectrum parameters. 
 
     
     
       7. The light-measuring method of  claim 1 , wherein the three actual stimulus values are corresponded to three actual color-matching functions of the light-measuring system separately, the light-measuring method further comprises following steps of:
 calculating an analogue stimulus value according to the to-be-measured light spectrum parameter and one of the three actual color-matching functions; 
 calculating an error value according to the to-be-measured light spectrum parameter, a standard color-matching functions and the three actual color-matching functions; and 
 calculating an estimated luminance of the to-be-measured light according to the ratio value of the error values and the analogue stimulus values, and according to the actual stimulus value corresponded to the three actual color-matching function. 
 
     
     
       8. The light-measuring method of  claim 1 , wherein the three actual stimulus values are corresponded to the three actual color-matching functions of the light-measuring system separately, the look-up table further comprises a plurality of reference error values, each reference error value is corresponded to one of the plurality of spectrum parameters, the light-measuring method further comprises following steps of:
 calculating an analogue stimulus value according to the to-be-measured light spectrum parameter and one of the three actual color-matching functions; 
 determining an error value according to at least one of the spectrum parameters of at least one of the reference error values; and 
 calculating an estimated luminance of the to-be-measured light according to the ratio value of the error value and the analogue stimulus value, and the actual stimulus value corresponded to the actual color-matching function. 
 
     
     
       9. The light-measuring method of  claim 8 , further comprising the following step of:
 calculating the plurality of corresponding reference error values according to the plurality of spectrum parameter, a standard color-matching function, and the actual color-matching function. 
 
     
     
       10. The light-measuring method of  claim 1 , wherein the three actual stimulus values are corresponded to three actual color-matching functions of the light-measuring system separately, the light-measuring method further comprises following steps of:
 calculating an analogue stimulus value according to the to-be-measured light spectrum parameter and one of the three actual color-matching functions; 
 calculating an analogue standard stimulus values according to the to-be-measured light spectrum parameter and a standard color-matching functions; and 
 calculating an estimated luminance of the to-be-measured light according to the ratio value of the analogue standard stimulus value and the analogue stimulus value, the actual color-matching functions and the actual stimulus values. 
 
     
     
       11. The light-measuring method of  claim 1 , wherein the three actual stimulus values are corresponded to three actual color-matching functions of the light-measuring system separately, the look-up table further comprises a plurality of reference adjustment coefficients, each reference adjustment coefficient is corresponded to one of the plurality of spectrum parameters, the light-measuring method further comprises following steps of:
 determining an adjustment coefficient according to at least one of the corresponded spectrum parameters of at least one of the reference adjustment coefficients; and 
 calculating an estimated luminance of the to-be-measured light according to the adjustment coefficient and one of the reference adjustment coefficients. 
 
     
     
       12. The light-measuring method of  claim 11 , wherein the three actual stimulus values are corresponded to an actual color-matching functions of the light-measuring system, the light-measuring method further comprises following steps of:
 calculating a plurality of reference stimulus values corresponded to the plurality of spectrum parameters according to the plurality of spectrum parameters and the actual color-matching function; 
 calculating a plurality of reference standard stimulus values corresponded to the plurality of spectrum parameters according to the plurality of spectrum parameters and a standard color-matching functions; and 
 calculating the corresponding reference adjustment coefficient according to the plurality of reference standard stimulus values and the plurality of reference stimulus values. 
 
     
     
       13. The light-measuring method of  claim 1 , wherein the three actual stimulus values are corresponded to an actual color-matching functions of the light-measuring system, the light-measuring method further comprises following steps of:
 calculating a spectral amplitude of the to-be-measured light according to the to-be-measured light spectrum parameter, one of the three actual color-matching functions and the actual stimulus value corresponded to the three actual color-matching functions; and 
 calculating an estimated luminance of the to-be-measured light according to the spectral amplitude, the to-be-measured light spectrum parameter and a standard color-matching function. 
 
     
     
       14. A light-measuring system, comprising:
 a light-sensing module comprising a light filtration element and a light-sensing element, the light-sensing module sensing at least one to-be-measured light to produce three actual stimulus values correspondingly; 
 a storage module for storing a look-up table, the look-up table comprising a plurality of spectrum parameters and a plurality of look-up color coordinates based on a light spectrum model, each look-up color coordinate corresponding to one of the plurality of spectrum parameters; and 
 a processing module, coupled to the light-sensing module and the storage module, calculating an actual color coordinate according to the plurality of actual stimulus values corresponded to each to-be-measured light, then the processing module determining at least one look-up color coordinate matched with the actual color coordinate according to the look-up table, and determining a to-be-measured light spectrum parameter according to at least one of the spectrum parameters of at least one of the matched look-up color coordinates; 
 wherein the processing module calculates three error values according to the to-be-measured light spectrum parameter, the three actual color-matching functions and three standard color-matching functions, then the three actual stimulus values are corrected by the three error values and calculates an estimated color coordinate. 
 
     
     
       15. The light-measuring system of  claim 14 , wherein the look-up table further comprises a plurality of error corrected parameters, each error corrected parameter comprises three reference error values corresponded to at least one of the plurality of spectrum parameters, the processing module determines three error values according to at least one of the error corrected parameters of at least one of the matched spectrum parameters, then calculates an estimated color coordinate. 
     
     
       16. A light-measuring system, comprising:
 a light-sensing module comprising a light filtration element and a light-sensing element, the light-sensing module sensing at least one to-be-measured light to produce three actual stimulus values correspondingly; 
 a storage module for storing a look-up table, the look-up table comprising a plurality of spectrum parameters and a plurality of look-up color coordinates based on a light spectrum model, each look-up color coordinate corresponding to one of the plurality of spectrum parameters; and 
 a processing module, coupled to the light-sensing module and the storage module, calculating an actual color coordinate according to the plurality of actual stimulus values corresponded to each to-be-measured light, then the processing module determining at least one look-up color coordinate matched with the actual color coordinate according to the look-up table, and determining a to-be-measured light spectrum parameter according to at least one of the spectrum parameters of at least one of the matched look-up color coordinates; 
 wherein the processing module calculates three analogue standard stimulus values according to the to-be-measured light spectrum parameters and three standard color-matching functions, then calculates an estimated color coordinate according to the three analogue standard stimulus values. 
 
     
     
       17. A light-measuring method for measuring a to-be-measured light by a light-measuring system according to a look-up table comprising a plurality of spectrum parameters and a plurality of look-up color coordinates based on a light spectrum model, each look-up color coordinate corresponding to one of the plurality of spectrum parameters, the light-measuring method comprising the following steps of:
 measuring the to-be-measured light by the light-measuring system, for obtaining actual stimulus values, and then calculating an actual color coordinate; 
 determining at least one of the look-up color coordinate matched with the actual color coordinate according to the actual color coordinate and the look-up table; 
 determining a to-be-measured light spectrum parameter according to at least one of the spectrum parameters of at least one of the matched look-up color coordinates; 
 calculating three analogue standard stimulus values according to the to-be-measured light spectrum parameter and three standard color-matching functions; and 
 calculating an estimated color coordinate of the to-be-measured light according to the three analogue standard stimulus values. 
 
     
     
       18. The light-measuring system of  claim 14 , wherein the light-sensing element comprises a plurality of light-sensing units, the plurality of light-sensing units are arranged to form a one-dimensional array or a two-dimensional array.